My opinion is that if the L foot has enough surface area it constitutes
a flashing, and that large flashings can actually cause more damage to
the roof than they prevent.
I also agree that an attachement doesn't constitute a penetration. I
just finished an install on a metal roof with hundreds of screw holes.
We added a few more screw holes, and ours have 20 times the sealant
surface area. We did run a 1" conduit through the roof, and since it
was an actual penetration, we used a very expensive flexible boot flashing.
Personally, I think we need about a 3"x3" or 4" x 4" L foot with a
double stick butyl tape on the bottom, and all will be well.
I realize that the OP was referring to asphalt, but I will flash other
roof types that don't do well with L feet ( like shake).
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
On 8/6/2015 12:59 PM, Conrad Geyser wrote:
Hi fellow Wrenches,
Flashing -
We have ~30 years experience with ~700 systems dating back to 1980
here in the Northeast primarily on asphalt shingles.
Standard attachment method on these historic systems and currently for
us is a lagged foot bedded in silicone. We've seen no leaks including
the historic systems as long as there was solid attachment to framing
and the foot size was big enough to not crush the roofing.
Our current technique is to use a single lag through the center of a
1.5" x 5" foot. Bed the foot 100% and run the lag in coated as well.
Fillet all "gush out" (you can look these terms up : >). Don't use
GE silicone below 45F - it will never cure.
For aspahlt here in the NE, I feel as though the flashing products are
OK but actually create more roof liability as they require the
releasing of shingles at a minimum.
Conrad Geyser
Cotuit Solar LLC
NAPCEP PV and Thermal
On Thu, Aug 6, 2015 at 1:16 PM, Matt Partymiller
<m...@solar-energy-solutions.com
<mailto:m...@solar-energy-solutions.com>> wrote:
Daniel,
My answer is to flash until others prove me wrong.
I am in the same position you are, speaking to the same
manufacturers you
are, and probably dealing with the same low competitor pricing you
are.
These products sure sound tempting.
Over the past decade I have probably removed a dozen 80's era hot
air or
hot water systems that were directly attached to roofs (installed by
others). In every instance the roof was a complete mess and
required deck
replacement. I now tell homeowners just to contact a roofer and
have them
dispose of the collectors in the process of re-roofing - we will
come out
after the new roof is in place.
I think you summed up the sealant problem quite well. I sell my
systems
as a 25 year product. I am not satisfied that butyl is a 25 year
answer.
Until someone convinces me otherwise, I will relate as much to my
customers and proceed with proper flashings.
Good poll.
Matt
Matthew Partymiller
Solar Energy Solutions LLC
(877) 312-7456 <tel:%28877%29%20312-7456>
m...@solar-energy-solutions.com
<mailto:m...@solar-energy-solutions.com>
On Thu, August 6, 2015 12:47 pm, Daniel Young wrote:
> Writing the subject above, it seems like I've heard this
question on the
> wrench list before, but I could not find it in my old email
archives. Feel
> free to pint me back to the old discussion if it's there.
>
>
>
> I've been using a flashing based roof attachment for 8+yrs now
(quick
> mount or similar). Now we are looking at Rail-less systems
(quick rack is
> a good example). There is also a non-flashed rail-less racking from
> roof-tech http://roof-tech.us/ . I've always been of the opinion
that
> simply crushing some sealant/gasket onto an asphalt shingle work
fine at
> first (the test data from roof-tech is impressive), but would be
an issue
> 10+yrs down the
> road (thermal expansion movement, freeze/thaw, etc). I can make
a good
> waterproof seal at first by just slathering some butyl/silicone
to an
> L-foot
> and cranking it down on the shingles, but that practice really
disappeared
> 8+yrs ago.
>
>
>
>
> Maybe consider this a Poll: (to flash, or not to flash)
>
>
>
>
> With Regards,
>
>
>
>
> Daniel Young,
>
>
> NABCEP Certified PV Installation ProfessionalTM: Cert #031508-90
>
>
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